Apparatus for treating wells



L. B. SCOTT APPARATUS FOR TREATING WELLS Sept. 26, 1961 Filed April ll, 1957 4 Sheets-Sheet 1 INVENTOR. 4/5 5, 56077" BY nl inve/1f# Sept. 26, .1961 1 B. SCOTT 3,001,584

APPARATUS FOR TREATING WELLS Sept.. 26, 1961 L. B. scoTT APPARATUS FOR TREATING WELLS Filed April 1l, 1957 4 Sheets-Sheet 3 .9 9 4 65 y 4 4/ 4 4 m4n f /4/ m4 4 EC 2 1 n FO m l IE 1 l ,izl No 15. 7 4 44 4 0 f l, 4 44. 45 @4 4 444W@ w44 4/.. 0 0/ 5 4 f Y 5 B ,n 7 5 4 4 4 4,4 44 4 A7 4 Q4 f 4 4 5 4 s 44 4 74 4 5 x 4 y /MN/ /47 x\\\\u 4 4 4 4 4, 5 4 4 4 Sept. 26, 1951 L. B. scoTT 3,001,584

APPARATUS FOR TREATING WELLS 7 BY E v/ United States Patent Olice Patented Sept. 26, 1961 3,001,584 APPARATUS FOR 'IREATING WELLS Lyle B. Scott, South Gate, Calif., assignor to BJ Service, Inc., Long Beach, Calif., a corporation of Delaware Filed Apr. 11, 1957, Ser. No. 652,286 13 Claims. (Cl. 1156-63) The present invention relates to an improved well treating apparatus.

In the eld of treating oil and gas wells, it frequently becomes desirable to inject uid down into the well for treating the earth formation traversed by the well as in formation fracturing, acidizing, cleaning and other fluid operations, as -well as in cementing or the like. Relatively high fluid pressures and/or injection rates are often required in order for the treatment to be effective. Despite the availability of pump pressure at the well head, adequate downhole pressures are oftentimes diliicult to attain because of friction losses, depending upon the viscosity of the treating fluid, whether the huid is being pumped down tubing or down casing, into an open hole or into the formation through casing perforations, and other factors.

In fracturing earth formation to enhance the flow of oil into the well from relatively impermeable strata or to provide communication between the well and blocked oil bearing strata or sands to enable production thereof, fluid is pumped into the Well Aunder pressure for overcming the stresses of adjacent tight or impermeable strata to form fissures or cracks radiating from the well, such cracks resulting in -actual fracturing of rock or shale formations, or the like, having a yield point at which they will rupture responsive to internal tension. In the case of formations having existing tight fractures, the fracturing uid merely overcomes the conning stress and opens the existing fractures, such as exist at boundries or the bed plane of different strat-a. Higher pressures are required to effect actual fracturing of the rock or other formation than are required for opening existing fractures, whereas lower viscosity uids and higher injection rates are generally required in the latter case.

Depending upon the rate of loss of `:fluid into the formation, the depth of the Well, and the viscous properties of the treating or fracturing uid, as Well as upon the capacity of the surface pumps to provide high injection rates and/ or pressures, sufficient pressures and/or injection rates may at times be practically unattainable. Means for providing a single-stroke, pump-like boost to the fluid pressure to implement available surface pump pressure are disclosed in the copending patent application of Lyle B. Scott and Mathew B. Riordan, Jr., filed October 16, 1956, Serial No. 616,333 for Well Treating Method and Apparatus.

According to the invention of that application, a container of low-propellant or rocket-type fuel is disposed in the Well adjacent to, or just above, the producing or potentially productive zone to be fractured or otherwise treated. Without interrupting the iiow of fluid from the surface pumps, the propellant is ignited or detonated so as to produce a large volume of gas pressure which is, so to speak, super-imposed upon the pump pressure to p'rovide a powerful boost or assist to the effective pressure of the treating uid-, which in a fracturing operation may be required to lift ythe overburden at the zone of fracture. Such overburden of ordinary sedimentary formation applies a vertical stress of' approximately 1.0 p.s.i. per foot of depth, although this .may vary due to the overlying weight of some strata being borne by a briding action caused by earth movements. Therefore, in relatively deep wells, substantial pressures must be developed in' order to effect fracturin'g.

The detonation or ignition of the propellant or rocket fuel charge aforementioned is adapted to supply, in addition to the pump pressure which may be inadequate for effective fracturing, a pulse-like pressure boost of thousands of pounds, thus enabling initial opening of the formation by the creation of new, or opening of old, fractures. Following such initial opening, continued pump pressure is adequate to open the formation further, so that fractures radiating from the well may be of substantial extent, depending upon the differences in stress between adjacent formations through which the fractures extend and the borehole wall being fractured. Such fractures may extend radially of the well upwards of 1,000 feet or more.

A primary object of the present invention is to provide an improved apparatus of the type disclosed in the aforementioned copending patent application, the apparatus hereof having a novel firing head for detonating the propellant or rocket fuel responsive to engagement of theV firing head by a plug, ball, or other element adapted to be inserted into the treating fluid at the well head and to moge therewith or therethrough into contact with the tiring ea Another object is to provide a :firing head in accordance with the preceding objective, including means for detonating firing means for the propellant or rocket fuel, responsive to engagement of the firing head by the plug, ball, or the like, while leaving the apparatus free of 0bstruction `to continued how of treating huid therethrough.

A further object of the invention is to provide an apparatus for producing vertical fractures in the earth formation traversed by a well bore, it being intended that the term vertical as employed herein contemplates fractures which are not necessarily truly vertical, but which may be disposed at a substantial angle relative to a vertical plane.

In wells where the tensile strength of the surrounding formation is high and vertical compressive strengths are low, pressure fluid will leak off into bedding planes or high permeability sections and will help to start so-calle'd horizontal fractures. When native fractures exist, a stress Wedge is provided by the pressure fluid which will open the native fractures at a pressure which may be less than the least stress in the surrounding formation. If such native fractures and high permeability areas are sealed olf, thus causing uniform pressure distribution around the hole, initial fracture will occur in a plane Where rock or formation strength is lowest. Such fractures will usually be vertical, or at least nearly so, but may, depending upon varying formation strength characteristics, vary to the point of being nearly horizontal.

Still another object is to provide huid injection apparatus including a container adapted to be disposed in a tubing string and run down a well to a position adjacent to the earth formation to be treated, the container having a flow passage communicating with said tubing, said container also having a chamber containing a material capable of generating gas upon ignition, and a tiring head for igniting the gas-generating material, and actuator means for the firing head adapted to be injected into the tubing to travel in the fluid in the well into engagement with the firing head for operating the same, said firing head including an axially moveable sleeve having a huid flow passage therein, a seat at the bottom of said sleeve on which the actuator means is adapted to seat as a valve, and by-pass openings in the sleeve, said bypass openings being closed when the sleeve is iu a normal position, whereby when the actuator means seats in the sleeve as a valve, the sleeve will be moved downwardly to a position where said by-pass openings are opened for the passage of uid therethrough, and means operative responsive to such downward movement of th sleeve to fire the firing means and effect gas generation by said gas-generating material. Other objects and advantages of the invention will be hereinafter defined or will become apparent to those skilled in the art, and the Vnovel features thereof will be defined in the appended claims.

In the accompanying drawings:

' FIG. l is a longitudinal sectional View of a tool embodying the invention;

FIG. 2 is an enlarged fragmentary sectional view, as taken longitudinally through the firing head of FIG. 1, with the firing head in a normal non-operating condition, md showing in broken lines an actuator ball valve there- FIG. 3 is an enlarged fragmentary sectional view, as taken longitudinally of the firing head, with certain of the parts shown in Yelevation and in Itheir respective nonoperating positions;

FIG. 4 is a view similar to FIG. 2, but showing the parts in the positions they assume upon downward movementof the operating sleeve responsive to seating of the ball valve in the sleeve, just prior to the tiring of the firing means;

FIG. 5 is an enlarged fragmentary view in longitudinal section, showing certain of the parts in elevation and in the relative positions shown in FIG. 4;

FIG. 6 is'a View similar to FIGS. 2 and 4, but showing the parts in a tiring position;

FIG. 7 is an enlarged fragmentary view in longitudinal section showing certain of the parts in elevation and in the relative positions shown in FIG. 6; Y f FIG. 8 is a transverse sectional view on an enlarged scale, as taken on the line 8 8 of FIG. 1;

FIG. 9 is a transverse sectional view on an enlarged scale, as taken on the line 9 9 of FIG. 1; and

FIG. 10 is an enlarged fragmentary view in vertical section as taken axially through'the ball seat, with an actuator ball shown in full lines seated thereon.

Like reference characters in the severalviews of the drawings and in the following description designate corresponding parts. i

' The apparatus shown in the accompanying drawings, referring particularly to FIGS. 1 and 2, generally cornprises a firing head section 1 and a lower propellant-containing chamber or receptacle 2. The illustrative embodiment is adapted to be interposed in a tubing string, and accordingly, the firing head is adapted for connect1on in such a tubing string (not shown) as by means of a tool joint 3, the propellant container or compartment 2 being adapted for connection in the tubing string as by means of a coupling or tool joint 4.

Otherwise, the assembly includes an elongated orifice tube generally designated T having an upper firing head section 6 and a lower propellant-container section 7, these tube sections 6 and 7 being threadedly interconnected with one another as at 8 and being concentrically disposed within coaxially extended firing head and propellant container cases 9 and 10 respectively. Adjacent to its lower end, the tiring head tubesection 6 is provided with aradially projecting adapter flange 11 against which the upper extremity of the propellant container case 10 abuts, with the case 10 held in tight abutting contact with the flange 11 by an interiorly threaded sleeve 12, threadedly engaged with the case 10 and having a radially inwardly projecting ilange 13 engaged with the ilange 11. The .tiring head case 9 abuts with the ilange 13 at the lower extremity of the case and is retained in position by means of a threaded nut 14 engaged with the threaded outer periphery of the tube section 6 and the upper end of the tiring head case 9. A spacer ring 16 is preferably disposed between the case 9 and the upper extremity of the tube section 6 and lwelded* to the tiring head case 9 as at 17.

Suitable sealing means such as a sealing ring 118 interposed between the spacer ring 16 and the iring head tube section 6, a sealing ring 18' interposed between the lower extremity of the tiring head casing 1 and the lower portion of tube section 6, a sealing ring 19 interposed between the upper extremity of the propellant compartment case 10 and the tube section 6, and a sealing ring 20 disposed at the base of the propellant chamber 10 are provided for sealing the firing head and the propel-V lant compartment against the entry of well fluids. The sealing ring 20 (see FIG. l) is interposed between an adapter sleeve 21, which is suitably mounted upon the exterior of the orifice tube section7, and a spacer ring 22 interposed between the sleeve 21 and the case 10 and preferably welded or otherwise suitably secured to the latter as at 23. A lock nut 24 threadedly engaged with the sleeve 21 aids in retaining the case 10 in place;

The propellant container 2 has disposed therein a quantity of gas-generating material, and without departing from the invention, such gas-generating material may be any of a number of diverse types, either liquid or solid. But for illustrative purposes, strips of a solid propellant material generally designated 25 are shown interposed in the annular space'between the case 10 and the orifice tube section 7, with a :tiring strip 26 interposed between the propellant strips 25 and the orifice tube section 7, and with an ignitor strip or ring 27 encircling the orice tube section 7 between the propellant strips 25 and suitable tiring mechanism which will be hereinafter more particularly described.

The propellant itself may, when a solid propellant such as herein disclosed is employed, consist of a slow burning propellant such as rubberized ammonium nitrate or the like. Such a solid propellant may be obtained, for example, from Grand Central Rocket Company, Montone, California, under their designations CBS-128K or CBS-12811. Alaternatively, it may consist of ordinary railroad fusee material, such as saw dust impregnated with sodium or ammonium nitrate, or it may consist of one of a variety of rocket fuels. Suitable propellants are described by T. L. Davis in Chemistry of Powder and Explosives, 1943, John Wiley & Son, Publishers. As is well known, these solid propellants may vary in their composition so as to burn at varying rates, but when ernployed in the present invention, a burning time of on the order of about ten seconds is preferable. Such burning of the propellant material will result in the generation of a high volume of gas within the sealed annular space between the case 10 and the orifice tube section 7.

A suitable number of gas relief plugs 28 are threadedly mounted in the orifice tube section 7, these relief plugs each having an orifice 29 therethrough sealed by means of a frangible disc 30 which, when subjected to high internal gas pressures, will rupture and allow the escape of gas from the gas chamber between the case 10 and the orifice tube 7 into the passage through the latter. The result of the generation of such gas and escape thereof through the orifice tube will be more particularly described hereinafter. Y Within the case 9 is suitable means for effect-ing firing or detonation of the propellant material, and more particularly, the ignitor strip 27. To this end, a suitable number of axially extended openings are formed through a radial orifice tube enlargement .31 on the firing head tube section 6, from which the ,adapter flange 11 projects, these openings being designated 32 and each having disposed therein a blank cartridge 33. The tiring head tube section 6 is provided with a peripheral groove or channel 34 in which is disposed an annular breech block 35, the breech block 35 being constituted of a U-shaped section 36 partially embracing the firing head tube section 6 in the groove 34 and a retaining section 37 which is secured to the tiring head tube section 6 as by means of a suitable number of screw fasteners 37a (see FIGS. 5 and 8).

Shiftably mounted in the breech block 35 and disposed for engagement with the blank cartridges 53, is a like number of firing pins 38 which, upon receiving aV sharp percussive blow, will tire the blank cartridges, thus in turn igniting or firing the propellant material. The means for providing such a percussive blow to the tiring pins 38 includes an annular hammer 39 disposed between the ring head tube section 6 and the firing 'head case 9. At opposite sides thereof, the hammer 39 is preferably provided with a pair of generally AL-shaped slots 40, with a like number of pins 41 threadedly fixed to the tiring head tube section 6 and projecting into the slots 40, so that when the pins 41 are disposed in the off-set base portions of the L-shaped slots 40, the hammer 39 will be retained against axial shifting movements, whereas upon slight rotative movement of the annular hammer 39, the elongated portions of the slots 40 will enable axial movement of the hammer 39 into Vengagement with the tiring pins 38.

An axially extended operator member 42 is lslidably mounted upon the outer periphery of the tiring head tube section 6, this actuator member 42 having a radially outwardly projecting flange or shoulder 43 thereon, disposed in opposed spaced relation to the upper extremity of the annular hammer 39. A coiled spring 44 is disposed between the shoulder -43 and the latter end of the hammer 39 so as to normally `bias the hammer towards the tiring pins 38. Means are provided for shifting the -actuator member 42 axially, such means including an actuator sleeve 45 slidably mounted within the tiring head tube section 6. A number of axially extended slots 46 are formed in the ring head tube section 6, and a number of lugs 47 project through the slots 46 and are connected to the upper extremity of the actuator member 42 as by means of a suitable number of screw fasteners 48, these lugs 47 being seated in an annular groove 49 in the outer periphery of the actuator sleeve 45 so that the actuator member 42 and the sleeve 45 are moveable axially as a unit. Preferably, sealing rings 45', 45' are interposed between the actuator sleeve 45 and the tiring head tube section 6 to prevent the passage of fluid into operating mechanism.

Referring particularly to FIGS. 3 and 7, the hammer 39 is provided with a pair of radially, inwardly projecting, pins 50 and 51, these pins being spaced from one another both in an axial direction and in a circumferential direction with relation to the hammer 39. The pin 51 is adapted to cooperate with an inclined cam surface 51 on the actuator member 42 so that upon engagement by the pin 51 responsive to axial movement of the actuator member 42, the hammer 39 will cam rotatively in a direction to unseat the pins 41 from the bases of the L-shaped slots 40, thus freeing the hammer 39 foraxial movement responsive to the pressure applied thereto by the spring 44. The actuator member I42. is provided with a longitudinally extended slot 50 having a cam surface 50 engageable with the pin 50, so that axial movement of the hammer 39 in the opposite direction will effect camniing of the hammer 39 rotatively in a direction whereby the pins 41 are moved into the bases of the `slots 40.

The structure thus far described is merely illustrative of a construction which is particularly adapted for use in connection with actuator means embodying the invention, and is described in particular detail in the copending application of Mathew B. Riordan, Jr., and Lyle B. Scott, filed October 16, 1956, Serial No. 616,333 for Well Treating Method and Apparatus. Illustratively, it is to be understood that the impact producing hammer means may, if desired, be of the type disclosed in my copending application, Serial No. 638,375, tiled February 5, i957, for Firing Head for Formation Treating Apparatus.

However, as has Vbeen hereinbefore pointed out, the apparatus hereof'is particularly well-suited for the performance of vertical fracturing operations, wherein the fractures are more or less vertical; lthat is, fracturing the earth formation by overcoming the lateral or horizontal stresses 'in the surrounding earth formation as 'dis- 6 tinguished from the longitudinal or vertical compressive stresses. Y

Accordingly, the actuator sleeve 45 is provided with lau annular seat member 52 at its base, and extending upwardly in thesleeve 45 from closely adjacent the seat 52 is a plurality of circumferentially spaced by-pass orifices or openings 53. Preferably these oriiices 53 are of such a size and configuration that their overall area is at least equal to or greater than the opening through the seat 52. Formed in the inner periphery of the tiring head tube section 6 is an annular by-pass chamber 54 so that when the openings 53 of the sleeve 45 register with the by-pass chamber 54, fluid passing downwardly through the sleeve 45 will flow through theA orifices 53 and the by-pass chamber 54 and thence on through the tube sections 6 and 7. The outer periphery of the annular seat member 52 is preferably of a slightly smaller diameter than the inside diameter of the firing head tube section 6, so that a limited uid flow is permitted past the member 52 to prevent sand clogging in certain fracturing operations where sand or some other propping agent is employed inthe iluid.

However, when the operator sleeve 45 is in the position shown in FIG. 2 where it is normally maintained by the pressure of the spring 44, the orices or openings 53 in the sleeve 45 will be closed olf by the inner periphery of the tiring head tube section 6 so that fluid passing downwardly through the sleeve 45 will ow through the seat 52 until such time as a check valve or the like engages With said seat 52 to deter such tloW. Y vSuch a check valve is herein shown as being constituted by a ball 55 having a diameter slightly greater than the seat 52, but of such a. size as to freely pass downwardly through the sleeve 45 into engagement with the seat 52. The ball 55 may be injected into the well through a suitable lubricator mechanism at the well head (not shown), which is shown and described in the copending Scott and Riordan application above referred to. Y

As the ball passes down through the tubing into engagement with the seat 52, the further free ow of fluid through the sleeve 45 will be prevented or minimized. Therefore, continued operation of the surface pumps, as is customary, will force the sleeve 45 downwardly until the duid is free to pass through the orifices 53 and into the by-pass chamber 54, thus resulting in Atiring of the blank cartridges 33. lf desired, the ball 55 may be composed of a soft material such as aluminum or a deformable plastic material such as nylon so that in the event of blockage of the by-pass orice 53, a build up of pressure behind the ball 55 within the sleeve 4S will extrude the ball through the seat 52.

In the use of the apparatus described above, uid will be injected into the well through a tubing string in which the apparatus is interposed. In a vertical fractur-ing operation, such uid will preferably be of a so-called low uid loss type; that is, of a type consisting of a gelled hydrocarbon such as kerosene or gasoline having a relatively high viscosity, but having the characteristic of vnot materially retarding the injection rate by virtue of the increase in viscosity due to gelling. In addition, the uid preferably will include a suitable well-known iluid loss preventing material which will form a filter cake upon the wall of the bore hole in those areas where iluid tends to ow out into the formation. Such duid will be pumped down into the hole until such time as the pumps may be halted and pressure retained in the Well. Indeed, it may require building up in increments to an internal pressure in the well just below the incipient breakdown pressure of the formation to be fractured; that is, the well will be pressurized up to a point and the pumps shut down to determine whether the pressure will hold. And such operation may be repeated until the well will hold the desired pressure.

With the surface pumps halted, the ball valve :55 may then be injected into the well without relieving the pressure and allowed to settle down in the tubing until it rests upon the seat 52, thus precluding lfree ow ofv uid through the firing head, whereupon recommencement of the pumps will exert a pressure upon the ball, thereby moving the actuator sleeve 45 downwardly. Such movement of the actuator sleeve will effect a corresponding downward movement of the member 42 with the result that the cam surface 51 thereon engaging with the pin 51 will elect rotation of the hammer 39 until the pins41 are released from the off-set bases of the slots 40 and the spring 44 forcesrtheY hammer 39 into'contact with the firing pins 38. Thus, the cartridges 33 will be fired, the propellant or4 rocket fuel ignited or detonated, and a high volume of gas will be generated in the annular space between, the-orifice tube section 7 and the propellant cont'ainer case 10. The frangible discs 30 will accordingly be blownA out by the gas pressure and the gas will escape into the orifice tube section 7 and exert a sudden impulse of high pressure on the uid therebeneath with the result that the earth formation will be fractured. Since the low iiuid yloss characteristics of the fracturing uid and the uid loss preventing material therein will prevent the flowoff of fluid into the formation through native fractures or through porous areas of high permeability, no pressure wedges will be forced off into the formation such as Y would ordinarily tend to produce a horizontal fracture.

Y above described, such use is merely exemplary, since the structure is also adapted for use in ordinary fracturirig operations, where the pumps at the surface lare not interrupted, and the ball valve 55 may be injected into the stream of Huid as it is being pumped downhole. Indeed the Vapparatus may also be employed in a variety of fluid Y injection well treatments as hereinabove pointed out.

` While the specific details of the apparatus hereof have been specifically shown and described, changes and alteraan opening to permit the discharge of gas into the well, shi-ftable means for effecting tiring of the gas-generating material, and means for shifting the shiftable means, that improvement Vwherein said shifting means includes a member having a fluid ow passage therethrough, and including means for effecting movement of said member with the treating uid, said member having means for bypassing said fluid upon predetermined movement of said member.

g 4. In apparatus for use in uid injection apparatus for treating wells, including a container of material capable of generating a large volume Yof gas uponi'gnition and adapted to be disposed in the well, Vsaid container having an opening to permit the discharge rof gas into the well, shiftable means Ifor effecting tiring the gas-generating material, and means for shifting the shiftable means, that improvement wherein said shifting means includes a member having a uid flow passage therethrough, said member having a valve seat therein, and a valve engageable with the seat responsive to the tlow of Vfluid through the member-to close said'ow passage, whereby said member will move with thefluid, said member also having means for by-passing the fluid around said valve responsive to movement of the member beyond a predetermined distance. Y r 5. Fluid injection apparatus comprising a tube having a uid passage therethrough, a container of gas-generating material on said tube,lmeans carried by said tube for initiating gas generation ofrsaid material, said container having an opening to'permit'the discharge of gas into the well, and operating means'forV said initiating means, said operating means including a member shiftably disposed in said fluid passage and having a ilu'idopening therethrough, means responsive tothe ow of iluid in one direction through said opening 'forblocking said opening to effect shifting of said. member withl the fluid, said member havingby-pass means for allowing uid to pass said f blocking means upon movement of Vthe member to a tions may be resorted to without departing from the spirit Y of the invention as deiined in the appended claims.

V I claim:

Y l. Fluid injection apparatus for a well, comprising a tube,.means defining with said tube -a container for a material capable of generating gas upon ignition, said container .having-an opening to permit the discharge of gas into the well, iiring means for said gas-generating material carried by said tube and including an actuator sleeve disposed in said tube for axial movements, a seat on said sleeve, and a valve engageable with said seat to prevent the' ow of fluid through said sleeve for causing said sleeve to be moved axially by said uid, said sleeve having means for by-passing fluid around said valve upon limited axial movement of the sleeve to actuate said firing means.V

' 2. Fluid injection apparatus for a well, comprising a Y. tube, means deiining with said tube a container for a material capable of generating gas upon ignition, said container having an opening to permit the discharge, of gas v intothe well, ring means for said gas-generating material carried by said tube and including an actuator sleeve disposed V,in said tube for axial movements, a seat on said sleeve, and a valve engageable with said sent to prevent theow of fluid through said sleeve for causing said sleeve to be moved axially by said uid, said sleeve having 'oy-pass ports therein for by-passing uid around said valve upon `limited axial movement of the sleeve'to actufate said'ring means. Y Y Y 3. In apparatus for use in tluid injection apparatus for treating wells, including a container of material capable .ofrgenerating a large-volume of gas upon ignition and adapted-to be disposed inthe'well, said container having position to effect operation of said initiating means.

6. VFluid injection apparatus as defined in claim 5, wherein saidblocking meansincludes a valve freely moveable inthe opening in the operating member, said member having a seat with which said valve is engageable. i

7. Fluid injection apparatus as defined in Yclaim 5, wherein said blocking means includes aV valveV freely Vmoveable in the opening in the operating member, said member having aseat with which said valve is engagea-ble, said valve being only slightly larger than said seat and being composed of a material enabling extruding of the valve through the seat upon being subjected to excessive pressure by said fluid.

8. Fluid injection appa-ratus comprising a tube having a huid passage therethrough, a containerxof gas-generating material on said tube, means carried by said tube for initiating gas generation of said material, said container having an opening to permit therdischarge of gas into the well, and operating means for said initiating means, said operating means including a member shiftably disposed in said vfluid passage and having a uid opening therethrough, means responsive to the ow of fluid in one direction through said opening for blocking said opening to e-ect shifting of said member with the uid, said ator sleeve and actuator member and extending through said slot, a seat on said sleeve in said sleeve passage, a valve member freely moveable -iu said sleeve passage along with uid owing through said passage for engaging said seat to block such ilow of iluid and effect movement of the sleeve in one direction, means normally maintaining said sleeve shifted in the other direction, and said sleeve having by-pass means for permitting the free ow of uid past said valve member upon limited movement of the sleeve in the fluid pressure responsive direction.

10. A fluid-pressure-operated actuator device as deined in claim 9, wherein said valve member is a ball.

11. A fluid pressure operated actuator device as dened in claim 9, wherein said sleeve has a reduced diameter about said seat providing a clearance between said sleeve and said tube, said clearance communicating with said by-pass means for allowing limited tlow of iluid past said valve when the sleeve is in its normal position aforesaid.

12. Fluid-pressure-operated actuator means of the class described comprising a tube having a lluid ow passage therethrough, an actuator sleeve slidably disposed in said passage, said sleeve also having a uid passage therethrough, said tube having a slot extending therethrough and longitudinally thereof, an actuator member disposed externally of said sleeve, means interconnecting said actuator sleeve and actuator member and extending through said slot, a seat on said sleeve in said sleeve passage,

a valve member freely moveable in said sleeve passage along with fluid owing through said passage for engaging said seat to block such ow of uid and effect movenient of the sleeve in one direction, means normally maintaining said sleeve shifted in the other direction, said sleeve having a by-pass port at one side of said seat, and said tube having a by-pass opening communicable with said port upon limited movement of the sleeve in the fluid pressure responsive direction.

13. Fluid-pressure-operated actuator means of the class described comprising a tube having a fluid ow passage therethrough, an actuator sleeve slidably disposed in said passage, said sleeve also having a fluid passage therethrough, said tube having a slot extending therethrough and longitudinally thereof, an actuator member disposed externally of said sleeve, means interconnecting said actuator sleeve and actuator member and extending through said slot, a seat on said sleeve in said sleeve passage, a valve member freely moveable in said sleeve passage along with uid flowing through said passage for engaging said seat to block such iiow of iluid and efect movement of the sleeve in one direction, means normally maintaining said sleeve shitted in the other direction, said sleeve having a plurality of longitudinally extended bypass por-ts at one side of the seat, said ports having a total area substantially comparable to the cross-sectional area of the tube passage, and said tube having an annular depression in its inner periphery dening a by-pass chamber communicable with said ports upon limited uid pressure responsive movement of said sleeve.

References Sited in the tile of this patent UNITED STATES PATENTS 2,488,819 Larkin Nov. 22, 1949 2,651,368 Baker et al. Sept. 8, 1953 2,696,259 Greene Dec. 7, 1954 

